include/libc-symbols.h

   1 /* Support macros for making weak and strong aliases for symbols,
   2    and for using symbol sets and linker warnings with GNU ld.
   3    Copyright (C) 1995-1998,2000-2003,2004, 2005 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #ifndef _LIBC_SYMBOLS_H
  22 #define _LIBC_SYMBOLS_H 1
  23
  24 /* This file's macros are included implicitly in the compilation of every
  25    file in the C library by -imacros.
  26
  27    We include config.h which is generated by configure.
  28    It should define for us the following symbols:
  29
  30    * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'.
  31    * ASM_GLOBAL_DIRECTIVE with `.globl' or `.global'.
  32    * ASM_TYPE_DIRECTIVE_PREFIX with `@' or `#' or whatever for .type,
  33      or leave it undefined if there is no .type directive.
  34    * HAVE_GNU_LD if using GNU ld, with support for weak symbols in a.out,
  35    and for symbol set and warning messages extensions in a.out and ELF.
  36    * HAVE_ELF if using ELF, which supports weak symbols using `.weak'.
  37    * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'.
  38    * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'.
  39
  40    */
  41
  42 /* This is defined for the compilation of all C library code.  features.h
  43    tests this to avoid inclusion of stubs.h while compiling the library,
  44    before stubs.h has been generated.  Some library code that is shared
  45    with other packages also tests this symbol to see if it is being
  46    compiled as part of the C library.  We must define this before including
  47    config.h, because it makes some definitions conditional on whether libc
  48    itself is being compiled, or just some generator program.  */
  49 #define _LIBC   1
  50
  51 /* Enable declarations of GNU extensions, since we are compiling them.  */
  52 #define _GNU_SOURCE     1
  53 /* And we also need the data for the reentrant functions.  */
  54 #define _REENTRANT      1
  55
  56 #include <config.h>
  57
  58 /* The symbols in all the user (non-_) macros are C symbols.
  59    HAVE_GNU_LD without HAVE_ELF implies a.out.  */
  60
  61 #if defined HAVE_ASM_WEAK_DIRECTIVE || defined HAVE_ASM_WEAKEXT_DIRECTIVE
  62 # define HAVE_WEAK_SYMBOLS
  63 #endif
  64
  65 #ifndef __SYMBOL_PREFIX
  66 # ifdef NO_UNDERSCORES
  67 #  define __SYMBOL_PREFIX
  68 # else
  69 #  define __SYMBOL_PREFIX "_"
  70 # endif
  71 #endif
  72
  73 #ifndef C_SYMBOL_NAME
  74 # ifdef NO_UNDERSCORES
  75 #  define C_SYMBOL_NAME(name) name
  76 # else
  77 #  define C_SYMBOL_NAME(name) _##name
  78 # endif
  79 #endif
  80
  81 #ifndef ASM_LINE_SEP
  82 # define ASM_LINE_SEP ;
  83 #endif
  84
  85 #ifdef HAVE_ASM_GLOBAL_DOT_NAME
  86 # ifndef C_SYMBOL_DOT_NAME
  87 #  if defined __GNUC__ && defined __GNUC_MINOR__ \
  88       && (__GNUC__ << 16) + __GNUC_MINOR__ >= (3 << 16) + 1
  89 #   define C_SYMBOL_DOT_NAME(name) .name
  90 #  else
  91 #   define C_SYMBOL_DOT_NAME(name) .##name
  92 #  endif
  93 # endif
  94 #endif
  95
  96 #ifndef __ASSEMBLER__
  97 /* GCC understands weak symbols and aliases; use its interface where
  98    possible, instead of embedded assembly language.  */
  99
 100 /* Define ALIASNAME as a strong alias for NAME.  */
 101 # define strong_alias(name, aliasname) _strong_alias(name, aliasname)
 102 # define _strong_alias(name, aliasname) \
 103   extern __typeof (name) aliasname __attribute__ ((alias (#name)));
 104
 105 /* This comes between the return type and function name in
 106    a function definition to make that definition weak.  */
 107 # define weak_function __attribute__ ((weak))
 108 # define weak_const_function __attribute__ ((weak, __const__))
 109
 110 # ifdef HAVE_WEAK_SYMBOLS
 111
 112 /* Define ALIASNAME as a weak alias for NAME.
 113    If weak aliases are not available, this defines a strong alias.  */
 114 #  define weak_alias(name, aliasname) _weak_alias (name, aliasname)
 115 #  define _weak_alias(name, aliasname) \
 116   extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
 117
 118 /* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined).  */
 119 #  define weak_extern(symbol) _weak_extern (weak symbol)
 120 #  define _weak_extern(expr) _Pragma (#expr)
 121
 122 # else
 123
 124 #  define weak_alias(name, aliasname) strong_alias(name, aliasname)
 125 #  define weak_extern(symbol) /* Nothing. */
 126
 127 # endif
 128
 129 #else /* __ASSEMBLER__ */
 130
 131 # ifdef HAVE_ASM_SET_DIRECTIVE
 132 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 133 #   define strong_alias(original, alias)                                \
 134   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 135   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original) ASM_LINE_SEP      \
 136   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP           \
 137   .set C_SYMBOL_DOT_NAME (alias),C_SYMBOL_DOT_NAME (original)
 138 #   define strong_data_alias(original, alias)                           \
 139   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 140   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 141 #  else
 142 #   define strong_alias(original, alias)                                \
 143   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 144   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 145 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 146 #  endif
 147 # else
 148 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 149 #   define strong_alias(original, alias)                                \
 150   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 151   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 152   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP           \
 153   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 154 #   define strong_data_alias(original, alias)                           \
 155   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 156   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 157 #  else
 158 #   define strong_alias(original, alias)                                \
 159   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 160   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 161 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 162 #  endif
 163 # endif
 164
 165 # ifdef HAVE_WEAK_SYMBOLS
 166 #  ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
 167 #   ifdef HAVE_ASM_GLOBAL_DOT_NAME
 168 #    define weak_alias(original, alias)                                 \
 169   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original) ASM_LINE_SEP \
 170   .weakext C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
 171 #   else
 172 #    define weak_alias(original, alias)                                 \
 173   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
 174 #   endif
 175 #   define weak_extern(symbol)                                          \
 176   .weakext C_SYMBOL_NAME (symbol)
 177
 178 #  else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 179
 180 #   ifdef HAVE_ASM_GLOBAL_DOT_NAME
 181 #    define weak_alias(original, alias)                                 \
 182   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 183   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 184   .weak C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP                          \
 185   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 186 #   else
 187 #    define weak_alias(original, alias)                                 \
 188   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 189   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 190 #   endif
 191
 192 #   define weak_extern(symbol)                                          \
 193   .weak C_SYMBOL_NAME (symbol)
 194
 195 #  endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 196
 197 # else /* ! HAVE_WEAK_SYMBOLS */
 198
 199 #  define weak_alias(original, alias) strong_alias(original, alias)
 200 #  define weak_extern(symbol) /* Nothing */
 201 # endif /* ! HAVE_WEAK_SYMBOLS */
 202
 203 #endif /* __ASSEMBLER__ */
 204
 205 /* On some platforms we can make internal function calls (i.e., calls of
 206    functions not exported) a bit faster by using a different calling
 207    convention.  */
 208 #ifndef internal_function
 209 # define internal_function      /* empty */
 210 #endif
 211
 212 /* Prepare for the case that `__builtin_expect' is not available.  */
 213 #ifndef HAVE_BUILTIN_EXPECT
 214 # define __builtin_expect(expr, val) (expr)
 215 #endif
 216
 217 /* Determine the return address.  */
 218 #define RETURN_ADDRESS(nr) \
 219   __builtin_extract_return_addr (__builtin_return_address (nr))
 220
 221 /* When a reference to SYMBOL is encountered, the linker will emit a
 222    warning message MSG.  */
 223 #ifdef HAVE_GNU_LD
 224 # ifdef HAVE_ELF
 225
 226 /* We want the .gnu.warning.SYMBOL section to be unallocated.  */
 227 #  ifdef HAVE_ASM_PREVIOUS_DIRECTIVE
 228 #   define __make_section_unallocated(section_string)   \
 229   asm (".section " section_string "\n\t.previous");
 230 #  elif defined HAVE_ASM_POPSECTION_DIRECTIVE
 231 #   define __make_section_unallocated(section_string)   \
 232   asm (".pushsection " section_string "\n\t.popsection");
 233 #  else
 234 #   define __make_section_unallocated(section_string)
 235 #  endif
 236
 237 /* Tacking on "\n\t#" to the section name makes gcc put it's bogus
 238    section attributes on what looks like a comment to the assembler.  */
 239 #  ifdef HAVE_SECTION_QUOTES
 240 #   define __sec_comment "\"\n\t#\""
 241 #  else
 242 #   define __sec_comment "\n\t#"
 243 #  endif
 244 #  define link_warning(symbol, msg) \
 245   __make_section_unallocated (".gnu.warning." #symbol) \
 246   static const char __evoke_link_warning_##symbol[]     \
 247     __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \
 248     = msg;
 249 #  define libc_freeres_ptr(decl) \
 250   __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \
 251   decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment)))
 252 #  define __libc_freeres_fn_section \
 253   __attribute__ ((section ("__libc_freeres_fn")))
 254 # else /* Not ELF: a.out */
 255 #  ifdef HAVE_XCOFF
 256 /* XCOFF does not support .stabs.
 257    The native aix linker will remove the .stab and .stabstr sections
 258    The gnu linker will have a fatal error if there is a relocation for
 259    symbol in the .stab section.  Silently disable this macro.  */
 260 #   define link_warning(symbol, msg)
 261 #  else
 262 #   define link_warning(symbol, msg)            \
 263      asm (".stabs \"" msg "\",30,0,0,0\n\t"     \
 264           ".stabs \"" __SYMBOL_PREFIX #symbol "\",1,0,0,0\n");
 265 #  endif /* XCOFF */
 266 #  define libc_freeres_ptr(decl) decl
 267 #  define __libc_freeres_fn_section
 268 # endif
 269 #else
 270 /* We will never be heard; they will all die horribly.  */
 271 # define link_warning(symbol, msg)
 272 # define libc_freeres_ptr(decl) decl
 273 # define __libc_freeres_fn_section
 274 #endif
 275 #define libc_freeres_fn(name)   \
 276   static void name (void) __attribute_used__ __libc_freeres_fn_section; \
 277   text_set_element (__libc_subfreeres, name);                           \
 278   static void name (void)
 279
 280 /* A canned warning for sysdeps/stub functions.  */
 281 #define stub_warning(name) \
 282   __make_section_unallocated (".gnu.glibc-stub." #name) \
 283   link_warning (name, \
 284                 "warning: " #name " is not implemented and will always fail")
 285
 286 /* Warning for linking functions calling dlopen into static binaries.  */
 287 #ifdef SHARED
 288 #define static_link_warning(name)
 289 #else
 290 #define static_link_warning(name) static_link_warning1(name)
 291 #define static_link_warning1(name) \
 292   link_warning(name, "Using '" #name "' in statically linked applications \
 293 requires at runtime the shared libraries from the glibc version used \
 294 for linking")
 295 #endif
 296
 297 /* Declare SYMBOL to be TYPE (`function' or `object') and of SIZE bytes,
 298    when the assembler supports such declarations (such as in ELF).
 299    This is only necessary when defining something in assembly, or playing
 300    funny alias games where the size should be other than what the compiler
 301    thinks it is.  */
 302 #define declare_symbol(symbol, type, size) \
 303   declare_symbol_1 (symbol, type, size)
 304 #ifdef ASM_TYPE_DIRECTIVE_PREFIX
 305 # ifdef __ASSEMBLER__
 306 #  define declare_symbol_1(symbol, type, size) \
 307     .type C_SYMBOL_NAME (symbol), \
 308           declare_symbol_1_paste (ASM_TYPE_DIRECTIVE_PREFIX, type), size
 309 #  define declare_symbol_1_paste(a, b)  declare_symbol_1_paste_1 (a,b)
 310 #  define declare_symbol_1_paste_1(a,b) a##b
 311 # else /* Not __ASSEMBLER__.  */
 312 #  define declare_symbol_1(symbol, type, size) \
 313     asm (".type " __SYMBOL_PREFIX #symbol ", " \
 314          declare_symbol_1_stringify (ASM_TYPE_DIRECTIVE_PREFIX) #type \
 315          "\n\t.size " __SYMBOL_PREFIX #symbol ", " #size);
 316 #  define declare_symbol_1_stringify(x) declare_symbol_1_stringify_1 (x)
 317 #  define declare_symbol_1_stringify_1(x) #x
 318 # endif /* __ASSEMBLER__ */
 319 #else
 320 # define declare_symbol_1(symbol, type, size) /* Nothing.  */
 321 #endif
 322
 323
 324 /*
 325 \f
 326 */
 327
 328 #ifdef HAVE_GNU_LD
 329
 330 /* Symbol set support macros.  */
 331
 332 # ifdef HAVE_ELF
 333
 334 /* Make SYMBOL, which is in the text segment, an element of SET.  */
 335 #  define text_set_element(set, symbol) _elf_set_element(set, symbol)
 336 /* Make SYMBOL, which is in the data segment, an element of SET.  */
 337 #  define data_set_element(set, symbol) _elf_set_element(set, symbol)
 338 /* Make SYMBOL, which is in the bss segment, an element of SET.  */
 339 #  define bss_set_element(set, symbol)  _elf_set_element(set, symbol)
 340
 341 /* These are all done the same way in ELF.
 342    There is a new section created for each set.  */
 343 #  ifdef SHARED
 344 /* When building a shared library, make the set section writable,
 345    because it will need to be relocated at run time anyway.  */
 346 #   define _elf_set_element(set, symbol) \
 347   static const void *__elf_set_##set##_element_##symbol##__ \
 348     __attribute__ ((used, section (#set))) = &(symbol)
 349 #  else
 350 #   define _elf_set_element(set, symbol) \
 351   static const void *const __elf_set_##set##_element_##symbol##__ \
 352     __attribute__ ((used, section (#set))) = &(symbol)
 353 #  endif
 354
 355 /* Define SET as a symbol set.  This may be required (it is in a.out) to
 356    be able to use the set's contents.  */
 357 #  define symbol_set_define(set)        symbol_set_declare(set)
 358
 359 /* Declare SET for use in this module, if defined in another module.
 360    In a shared library, this is always local to that shared object.
 361    For static linking, the set might be wholly absent and so we use
 362    weak references.  */
 363 #  define symbol_set_declare(set) \
 364   extern char const __start_##set[] __symbol_set_attribute; \
 365   extern char const __stop_##set[] __symbol_set_attribute;
 366 #  ifdef SHARED
 367 #   define __symbol_set_attribute attribute_hidden
 368 #  else
 369 #   define __symbol_set_attribute __attribute__ ((weak))
 370 #  endif
 371
 372 /* Return a pointer (void *const *) to the first element of SET.  */
 373 #  define symbol_set_first_element(set) ((void *const *) (&__start_##set))
 374
 375 /* Return true iff PTR (a void *const *) has been incremented
 376    past the last element in SET.  */
 377 #  define symbol_set_end_p(set, ptr) ((ptr) >= (void *const *) &__stop_##set)
 378
 379 # else  /* Not ELF: a.out.  */
 380
 381 #  ifdef HAVE_XCOFF
 382 /* XCOFF does not support .stabs.
 383    The native aix linker will remove the .stab and .stabstr sections
 384    The gnu linker will have a fatal error if there is a relocation for
 385    symbol in the .stab section.  Silently disable these macros.  */
 386 #   define text_set_element(set, symbol)
 387 #   define data_set_element(set, symbol)
 388 #   define bss_set_element(set, symbol)
 389 #  else
 390 #   define text_set_element(set, symbol)        \
 391     asm (".stabs \"" __SYMBOL_PREFIX #set "\",23,0,0," __SYMBOL_PREFIX #symbol)
 392 #   define data_set_element(set, symbol)        \
 393     asm (".stabs \"" __SYMBOL_PREFIX #set "\",25,0,0," __SYMBOL_PREFIX #symbol)
 394 #   define bss_set_element(set, symbol) ?error Must use initialized data.
 395 #  endif /* XCOFF */
 396 #  define symbol_set_define(set)        void *const (set)[1];
 397 #  define symbol_set_declare(set)       extern void *const (set)[1];
 398
 399 #  define symbol_set_first_element(set) &(set)[1]
 400 #  define symbol_set_end_p(set, ptr)    (*(ptr) == 0)
 401
 402 # endif /* ELF.  */
 403 #else
 404 /* We cannot do anything in generial.  */
 405 # define text_set_element(set, symbol) asm ("")
 406 # define data_set_element(set, symbol) asm ("")
 407 # define bss_set_element(set, symbol) asm ("")
 408 # define symbol_set_define(set)         void *const (set)[1];
 409 # define symbol_set_declare(set)        extern void *const (set)[1];
 410
 411 # define symbol_set_first_element(set)  &(set)[1]
 412 # define symbol_set_end_p(set, ptr)     (*(ptr) == 0)
 413 #endif  /* Have GNU ld.  */
 414
 415 #if DO_VERSIONING
 416 # define symbol_version(real, name, version) \
 417      _symbol_version(real, name, version)
 418 # define default_symbol_version(real, name, version) \
 419      _default_symbol_version(real, name, version)
 420 # ifdef __ASSEMBLER__
 421 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 422 #   define _symbol_version(real, name, version) \
 423      .symver real, name##@##version ASM_LINE_SEP                        \
 424      .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##version)
 425 #   define _default_symbol_version(real, name, version) \
 426      .symver real, name##@##@##version ASM_LINE_SEP                     \
 427      .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##@##version)
 428 #  else
 429 #   define _symbol_version(real, name, version) \
 430      .symver real, name##@##version
 431 #   define _default_symbol_version(real, name, version) \
 432      .symver real, name##@##@##version
 433 #  endif
 434 # else
 435 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 436 #   define _symbol_version(real, name, version) \
 437      __asm__ (".symver " #real "," #name "@" #version "\n\t"    \
 438               ".symver ." #real ",." #name "@" #version)
 439 #   define _default_symbol_version(real, name, version) \
 440      __asm__ (".symver " #real "," #name "@@" #version "\n\t"   \
 441               ".symver ." #real ",." #name "@@" #version)
 442 #  else
 443 #   define _symbol_version(real, name, version) \
 444      __asm__ (".symver " #real "," #name "@" #version)
 445 #   define _default_symbol_version(real, name, version) \
 446      __asm__ (".symver " #real "," #name "@@" #version)
 447 #  endif
 448 # endif
 449 #else
 450 # define symbol_version(real, name, version)
 451 # define default_symbol_version(real, name, version) \
 452   strong_alias(real, name)
 453 #endif
 454
 455 #if defined HAVE_VISIBILITY_ATTRIBUTE \
 456     && (defined SHARED || defined LIBC_NONSHARED)
 457 # define attribute_hidden __attribute__ ((visibility ("hidden")))
 458 #else
 459 # define attribute_hidden
 460 #endif
 461
 462 #ifdef HAVE_TLS_MODEL_ATTRIBUTE
 463 # define attribute_tls_model_ie __attribute__ ((tls_model ("initial-exec")))
 464 #else
 465 # define attribute_tls_model_ie
 466 #endif
 467
 468 #ifdef HAVE_Z_RELRO
 469 # define attribute_relro __attribute__ ((section (".data.rel.ro")))
 470 #else
 471 # define attribute_relro
 472 #endif
 473
 474 /* Handling on non-exported internal names.  We have to do this only
 475    for shared code.  */
 476 #ifdef SHARED
 477 # define INTUSE(name) name##_internal
 478 # define INTDEF(name) strong_alias (name, name##_internal)
 479 # define INTVARDEF(name) \
 480   _INTVARDEF (name, name##_internal)
 481 # if defined HAVE_VISIBILITY_ATTRIBUTE
 482 #  define _INTVARDEF(name, aliasname) \
 483   extern __typeof (name) aliasname __attribute__ ((alias (#name), \
 484                                                    visibility ("hidden")));
 485 # else
 486 #  define _INTVARDEF(name, aliasname) \
 487   extern __typeof (name) aliasname __attribute__ ((alias (#name)));
 488 # endif
 489 # define INTDEF2(name, newname) strong_alias (name, newname##_internal)
 490 # define INTVARDEF2(name, newname) _INTVARDEF (name, newname##_internal)
 491 #else
 492 # define INTUSE(name) name
 493 # define INTDEF(name)
 494 # define INTVARDEF(name)
 495 # define INTDEF2(name, newname)
 496 # define INTVARDEF2(name, newname)
 497 #endif
 498
 499 /* The following macros are used for PLT bypassing within libc.so
 500    (and if needed other libraries similarly).
 501    First of all, you need to have the function prototyped somewhere,
 502    say in foo/foo.h:
 503
 504    int foo (int __bar);
 505
 506    If calls to foo within libc.so should always go to foo defined in libc.so,
 507    then in include/foo.h you add:
 508
 509    libc_hidden_proto (foo)
 510
 511    line and after the foo function definition:
 512
 513    int foo (int __bar)
 514    {
 515      return __bar;
 516    }
 517    libc_hidden_def (foo)
 518
 519    or
 520
 521    int foo (int __bar)
 522    {
 523      return __bar;
 524    }
 525    libc_hidden_weak (foo)
 526
 527    Simularly for global data. If references to foo within libc.so should
 528    always go to foo defined in libc.so, then in include/foo.h you add:
 529
 530    libc_hidden_proto (foo)
 531
 532    line and after foo's definition:
 533
 534    int foo = INITIAL_FOO_VALUE;
 535    libc_hidden_data_def (foo)
 536
 537    or
 538
 539    int foo = INITIAL_FOO_VALUE;
 540    libc_hidden_data_weak (foo)
 541
 542    If foo is normally just an alias (strong or weak) of some other function,
 543    you should use the normal strong_alias first, then add libc_hidden_def
 544    or libc_hidden_weak:
 545
 546    int baz (int __bar)
 547    {
 548      return __bar;
 549    }
 550    strong_alias (baz, foo)
 551    libc_hidden_weak (foo)
 552
 553    If the function should be internal to multiple objects, say ld.so and
 554    libc.so, the best way is to use:
 555
 556    #if !defined NOT_IN_libc || defined IS_IN_rtld
 557    hidden_proto (foo)
 558    #endif
 559
 560    in include/foo.h and the normal macros at all function definitions
 561    depending on what DSO they belong to.
 562
 563    If versioned_symbol macro is used to define foo,
 564    libc_hidden_ver macro should be used, as in:
 565
 566    int __real_foo (int __bar)
 567    {
 568      return __bar;
 569    }
 570    versioned_symbol (libc, __real_foo, foo, GLIBC_2_1);
 571    libc_hidden_ver (__real_foo, foo)  */
 572
 573 #if defined SHARED && defined DO_VERSIONING \
 574     && !defined HAVE_BROKEN_ALIAS_ATTRIBUTE && !defined NO_HIDDEN
 575 # ifndef __ASSEMBLER__
 576 #  if !defined HAVE_VISIBILITY_ATTRIBUTE \
 577       || defined HAVE_BROKEN_VISIBILITY_ATTRIBUTE
 578 #   define __hidden_proto_hiddenattr(attrs...)
 579 #  else
 580 #   define __hidden_proto_hiddenattr(attrs...) \
 581   __attribute__ ((visibility ("hidden"), ##attrs))
 582 #  endif
 583 #  define hidden_proto(name, attrs...) \
 584   __hidden_proto (name, __GI_##name, ##attrs)
 585 #  define __hidden_proto(name, internal, attrs...) \
 586   extern __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
 587   __hidden_proto_hiddenattr (attrs);
 588 #  define __hidden_asmname(name) \
 589   __hidden_asmname1 (__USER_LABEL_PREFIX__, name)
 590 #  define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name)
 591 #  define __hidden_asmname2(prefix, name) #prefix name
 592 #  define __hidden_ver1(local, internal, name) \
 593   extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
 594   extern __typeof (name) __EI_##name \
 595         __attribute__((alias (__hidden_asmname (#local))))
 596 #  define hidden_ver(local, name)       __hidden_ver1(local, __GI_##name, name);
 597 #  define hidden_data_ver(local, name)  hidden_ver(local, name)
 598 #  define hidden_def(name)              __hidden_ver1(__GI_##name, name, name);
 599 #  define hidden_data_def(name)         hidden_def(name)
 600 #  define hidden_weak(name) \
 601         __hidden_ver1(__GI_##name, name, name) __attribute__((weak));
 602 #  define hidden_data_weak(name)        hidden_weak(name)
 603 # else
 604 /* For assembly, we need to do the opposite of what we do in C:
 605    in assembly gcc __REDIRECT stuff is not in place, so functions
 606    are defined by its normal name and we need to create the
 607    __GI_* alias to it, in C __REDIRECT causes the function definition
 608    to use __GI_* name and we need to add alias to the real name.
 609    There is no reason to use hidden_weak over hidden_def in assembly,
 610    but we provide it for consistency with the C usage.
 611    hidden_proto doesn't make sense for assembly but the equivalent
 612    is to call via the HIDDEN_JUMPTARGET macro instead of JUMPTARGET.  */
 613 #  define hidden_def(name)      strong_alias (name, __GI_##name)
 614 #  define hidden_weak(name)     hidden_def (name)
 615 #  define hidden_ver(local, name) strong_alias (local, __GI_##name)
 616 #  define hidden_data_def(name) strong_data_alias (name, __GI_##name)
 617 #  define hidden_data_weak(name)        hidden_data_def (name)
 618 #  define hidden_data_ver(local, name) strong_data_alias (local, __GI_##name)
 619 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 620 #   define HIDDEN_JUMPTARGET(name) .__GI_##name
 621 #  else
 622 #   define HIDDEN_JUMPTARGET(name) __GI_##name
 623 #  endif
 624 # endif
 625 #else
 626 # ifndef __ASSEMBLER__
 627 #  define hidden_proto(name, attrs...)
 628 # else
 629 #  define HIDDEN_JUMPTARGET(name) JUMPTARGET(name)
 630 # endif /* Not  __ASSEMBLER__ */
 631 # define hidden_weak(name)
 632 # define hidden_def(name)
 633 # define hidden_ver(local, name)
 634 # define hidden_data_weak(name)
 635 # define hidden_data_def(name)
 636 # define hidden_data_ver(local, name)
 637 #endif
 638
 639 #if !defined NOT_IN_libc
 640 # define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 641 # define libc_hidden_def(name) hidden_def (name)
 642 # define libc_hidden_weak(name) hidden_weak (name)
 643 # define libc_hidden_ver(local, name) hidden_ver (local, name)
 644 # define libc_hidden_data_def(name) hidden_data_def (name)
 645 # define libc_hidden_data_weak(name) hidden_data_weak (name)
 646 # define libc_hidden_data_ver(local, name) hidden_data_ver (local, name)
 647 #else
 648 # define libc_hidden_proto(name, attrs...)
 649 # define libc_hidden_def(name)
 650 # define libc_hidden_weak(name)
 651 # define libc_hidden_ver(local, name)
 652 # define libc_hidden_data_def(name)
 653 # define libc_hidden_data_weak(name)
 654 # define libc_hidden_data_ver(local, name)
 655 #endif
 656
 657 #if defined NOT_IN_libc && defined IS_IN_rtld
 658 # define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 659 # define rtld_hidden_def(name) hidden_def (name)
 660 # define rtld_hidden_weak(name) hidden_weak (name)
 661 # define rtld_hidden_ver(local, name) hidden_ver (local, name)
 662 # define rtld_hidden_data_def(name) hidden_data_def (name)
 663 # define rtld_hidden_data_weak(name) hidden_data_weak (name)
 664 # define rtld_hidden_data_ver(local, name) hidden_data_ver (local, name)
 665 #else
 666 # define rtld_hidden_proto(name, attrs...)
 667 # define rtld_hidden_def(name)
 668 # define rtld_hidden_weak(name)
 669 # define rtld_hidden_ver(local, name)
 670 # define rtld_hidden_data_def(name)
 671 # define rtld_hidden_data_weak(name)
 672 # define rtld_hidden_data_ver(local, name)
 673 #endif
 674
 675 #if defined NOT_IN_libc && defined IS_IN_libm
 676 # define libm_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 677 # define libm_hidden_def(name) hidden_def (name)
 678 # define libm_hidden_weak(name) hidden_weak (name)
 679 # define libm_hidden_ver(local, name) hidden_ver (local, name)
 680 # define libm_hidden_data_def(name) hidden_data_def (name)
 681 # define libm_hidden_data_weak(name) hidden_data_weak (name)
 682 # define libm_hidden_data_ver(local, name) hidden_data_ver (local, name)
 683 #else
 684 # define libm_hidden_proto(name, attrs...)
 685 # define libm_hidden_def(name)
 686 # define libm_hidden_weak(name)
 687 # define libm_hidden_ver(local, name)
 688 # define libm_hidden_data_def(name)
 689 # define libm_hidden_data_weak(name)
 690 # define libm_hidden_data_ver(local, name)
 691 #endif
 692
 693 #if defined NOT_IN_libc && defined IS_IN_libresolv
 694 # define libresolv_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 695 # define libresolv_hidden_def(name) hidden_def (name)
 696 # define libresolv_hidden_weak(name) hidden_weak (name)
 697 # define libresolv_hidden_ver(local, name) hidden_ver (local, name)
 698 # define libresolv_hidden_data_def(name) hidden_data_def (name)
 699 # define libresolv_hidden_data_weak(name) hidden_data_weak (name)
 700 # define libresolv_hidden_data_ver(local, name) hidden_data_ver (local, name)
 701 #else
 702 # define libresolv_hidden_proto(name, attrs...)
 703 # define libresolv_hidden_def(name)
 704 # define libresolv_hidden_weak(name)
 705 # define libresolv_hidden_ver(local, name)
 706 # define libresolv_hidden_data_def(name)
 707 # define libresolv_hidden_data_weak(name)
 708 # define libresolv_hidden_data_ver(local, name)
 709 #endif
 710
 711 #if defined NOT_IN_libc && defined IS_IN_libdl
 712 # define libdl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 713 # define libdl_hidden_def(name) hidden_def (name)
 714 # define libdl_hidden_weak(name) hidden_weak (name)
 715 # define libdl_hidden_ver(local, name) hidden_ver (local, name)
 716 # define libdl_hidden_data_def(name) hidden_data_def (name)
 717 # define libdl_hidden_data_weak(name) hidden_data_weak (name)
 718 # define libdl_hidden_data_ver(local, name) hidden_data_ver (local, name)
 719 #else
 720 # define libdl_hidden_proto(name, attrs...)
 721 # define libdl_hidden_def(name)
 722 # define libdl_hidden_weak(name)
 723 # define libdl_hidden_ver(local, name)
 724 # define libdl_hidden_data_def(name)
 725 # define libdl_hidden_data_weak(name)
 726 # define libdl_hidden_data_ver(local, name)
 727 #endif
 728
 729 #if defined NOT_IN_libc && defined IS_IN_libnss_files
 730 # define libnss_files_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 731 # define libnss_files_hidden_def(name) hidden_def (name)
 732 # define libnss_files_hidden_weak(name) hidden_weak (name)
 733 # define libnss_files_hidden_ver(local, name) hidden_ver (local, name)
 734 # define libnss_files_hidden_data_def(name) hidden_data_def (name)
 735 # define libnss_files_hidden_data_weak(name) hidden_data_weak (name)
 736 # define libnss_files_hidden_data_ver(local, name) hidden_data_ver(local, name)
 737 #else
 738 # define libnss_files_hidden_proto(name, attrs...)
 739 # define libnss_files_hidden_def(name)
 740 # define libnss_files_hidden_weak(name)
 741 # define libnss_files_hidden_ver(local, name)
 742 # define libnss_files_hidden_data_def(name)
 743 # define libnss_files_hidden_data_weak(name)
 744 # define libnss_files_hidden_data_ver(local, name)
 745 #endif
 746
 747 #if defined NOT_IN_libc && defined IS_IN_libnsl
 748 # define libnsl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 749 # define libnsl_hidden_def(name) hidden_def (name)
 750 # define libnsl_hidden_weak(name) hidden_weak (name)
 751 # define libnsl_hidden_ver(local, name) hidden_ver (local, name)
 752 # define libnsl_hidden_data_def(name) hidden_data_def (name)
 753 # define libnsl_hidden_data_weak(name) hidden_data_weak (name)
 754 # define libnsl_hidden_data_ver(local, name) hidden_data_ver (local, name)
 755 #else
 756 # define libnsl_hidden_proto(name, attrs...)
 757 # define libnsl_hidden_def(name)
 758 # define libnsl_hidden_weak(name)
 759 # define libnsl_hidden_ver(local, name)
 760 # define libnsl_hidden_data_def(name)
 761 # define libnsl_hidden_data_weak(name)
 762 # define libnsl_hidden_data_ver(local, name)
 763 #endif
 764
 765 #if defined NOT_IN_libc && defined IS_IN_libnss_nisplus
 766 # define libnss_nisplus_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 767 # define libnss_nisplus_hidden_def(name) hidden_def (name)
 768 # define libnss_nisplus_hidden_weak(name) hidden_weak (name)
 769 # define libnss_nisplus_hidden_ver(local, name) hidden_ver (local, name)
 770 # define libnss_nisplus_hidden_data_def(name) hidden_data_def (name)
 771 # define libnss_nisplus_hidden_data_weak(name) hidden_data_weak (name)
 772 # define libnss_nisplus_hidden_data_ver(local, name) hidden_data_ver (local, name)
 773 #else
 774 # define libnss_nisplus_hidden_proto(name, attrs...)
 775 # define libnss_nisplus_hidden_def(name)
 776 # define libnss_nisplus_hidden_weak(name)
 777 # define libnss_nisplus_hidden_ver(local, name)
 778 # define libnss_nisplus_hidden_data_def(name)
 779 # define libnss_nisplus_hidden_data_weak(name)
 780 # define libnss_nisplus_hidden_data_ver(local, name)
 781 #endif
 782
 783 #ifdef HAVE_BUILTIN_REDIRECTION
 784 # define libc_hidden_builtin_proto(name, attrs...) libc_hidden_proto (name, ##attrs)
 785 # define libc_hidden_builtin_def(name) libc_hidden_def (name)
 786 # define libc_hidden_builtin_weak(name) libc_hidden_weak (name)
 787 # define libc_hidden_builtin_ver(local, name) libc_hidden_ver (local, name)
 788 # ifdef __ASSEMBLER__
 789 #  define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name)
 790 # endif
 791 #else
 792 # define libc_hidden_builtin_proto(name, attrs...)
 793 # define libc_hidden_builtin_def(name)
 794 # define libc_hidden_builtin_weak(name)
 795 # define libc_hidden_builtin_ver(local, name)
 796 # ifdef __ASSEMBLER__
 797 #  define HIDDEN_BUILTIN_JUMPTARGET(name) JUMPTARGET(name)
 798 # endif
 799 #endif
 800
 801 #if defined NOT_IN_libc && defined IS_IN_libutil
 802 # define libutil_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 803 # define libutil_hidden_def(name) hidden_def (name)
 804 # define libutil_hidden_weak(name) hidden_weak (name)
 805 # define libutil_hidden_ver(local, name) hidden_ver (local, name)
 806 # define libutil_hidden_data_def(name) hidden_data_def (name)
 807 # define libutil_hidden_data_weak(name) hidden_data_weak (name)
 808 # define libutil_hidden_data_ver(local, name) hidden_data_ver (local, name)
 809 #else
 810 # define libutil_hidden_proto(name, attrs...)
 811 # define libutil_hidden_def(name)
 812 # define libutil_hidden_weak(name)
 813 # define libutil_hidden_ver(local, name)
 814 # define libutil_hidden_data_def(name)
 815 # define libutil_hidden_data_weak(name)
 816 # define libutil_hidden_data_ver(local, name)
 817 #endif
 818
 819 /* Get some dirty hacks.  */
 820 #include <symbol-hacks.h>
 821
 822 /* Move compatibility symbols out of the way by placing them all in a
 823    special section.  */
 824 #ifndef __ASSEMBLER__
 825 # define attribute_compat_text_section \
 826     __attribute__ ((section (".text.compat")))
 827 # define attribute_compat_data_section \
 828     __attribute__ ((section (".data.compat")))
 829 #else
 830 # define compat_text_section .section ".text.compat", "ax";
 831 # define compat_data_section .section ".data.compat", "aw";
 832 #endif
 833
 834 #endif /* libc-symbols.h */